[OpenMP] Handle non-function context before checking for diagnostic

emission

Ensure that we are in a function declaration context before checking
the diagnostic emission status, to avoid dereferencing a NULL function
declaration.

Differential Revision: https://reviews.llvm.org/D97573

clang/lib/Sema/SemaDecl.cpp

@@ -18341,6 +18341,8 @@ Decl *Sema::getObjCDeclContext() const {
 
 Sema::FunctionEmissionStatus Sema::getEmissionStatus(FunctionDecl *FD,
                                                      bool Final) {
+  assert(FD && "Expected non-null FunctionDecl");
+
   // SYCL functions can be template, so we check if they have appropriate
   // attribute prior to checking if it is a template.
   if (LangOpts.SYCLIsDevice && FD->hasAttr<SYCLKernelAttr>())

clang/lib/Sema/SemaOpenMP.cpp

@@ -1939,20 +1939,23 @@ Sema::SemaDiagnosticBuilder Sema::diagIfOpenMPHostCode(SourceLocation Loc,
                                                        FunctionDecl *FD) {
   assert(LangOpts.OpenMP && !LangOpts.OpenMPIsDevice &&
          "Expected OpenMP host compilation.");
-  FunctionEmissionStatus FES = getEmissionStatus(FD);
+
   SemaDiagnosticBuilder::Kind Kind = SemaDiagnosticBuilder::K_Nop;
-  switch (FES) {
-  case FunctionEmissionStatus::Emitted:
-    Kind = SemaDiagnosticBuilder::K_Immediate;
-    break;
-  case FunctionEmissionStatus::Unknown:
-    Kind = SemaDiagnosticBuilder::K_Deferred;
-    break;
-  case FunctionEmissionStatus::TemplateDiscarded:
-  case FunctionEmissionStatus::OMPDiscarded:
-  case FunctionEmissionStatus::CUDADiscarded:
-    Kind = SemaDiagnosticBuilder::K_Nop;
-    break;
+  if (FD) {
+    FunctionEmissionStatus FES = getEmissionStatus(FD);
+    switch (FES) {
+    case FunctionEmissionStatus::Emitted:
+      Kind = SemaDiagnosticBuilder::K_Immediate;
+      break;
+    case FunctionEmissionStatus::Unknown:
+      Kind = SemaDiagnosticBuilder::K_Deferred;
+      break;
+    case FunctionEmissionStatus::TemplateDiscarded:
+    case FunctionEmissionStatus::OMPDiscarded:
+    case FunctionEmissionStatus::CUDADiscarded:
+      Kind = SemaDiagnosticBuilder::K_Nop;
+      break;
+    }
   }
 
   return SemaDiagnosticBuilder(Kind, Loc, DiagID, FD, *this);

clang/test/OpenMP/simd_null_pointer_access.cpp

@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -fopenmp-simd -fsycl -fsycl-is-device -triple spir64 -verify -fsyntax-only %s
+
+// Test that in the presence of SYCL options, that null function
+// declarations are accounted for when checking to emit diagnostics.
+
+// expected-no-diagnostics
+
+__thread void *x;